Young male swimmer sounds really hot! (7)
I believe the answer is:
boiling
'hot' is the definition.
(similar in meaning)
'young male swimmer sounds really' is the wordplay.
I cannot quite understand how this works, but
'swimmer' could be 'ling' (ling is a type of fish) and 'ling' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for boiling that I've seen before include "Extremely hot" , "Seething" .)